Radio Frequency Identification also referred to as RFID is a well known method for auto-identification and tracking of an equipment or device. Specifically in hospitals asset tracking & remote monitoring of medical devices is becoming need of the hour. Further, especially in case of surgical equipments where sealable enclosure is preferred for sterilization of the equipment, it is necessary to read back or monitor vital parameters of the device such as number of use committed (for a multi-use device) without accessing the enclosed equipment. Therefore, without any external connectors or displays the only feasible method to monitor such devices is through wireless technology such as RFID.
Asset tracking by means of auto-identification utilizes RFID technology wherein an RFID tag storing a unique identification number is attached to a device or asset that uniquely defines the asset. An RFID reader is enabled to wirelessly interrogate the RFID tag attached to an asset by using RF field. Such RF field is received by the RFID tag that transmits the unique identification number to the RFID reader. An RFID tag may be a passive RFID tag that does not require a battery or an active RFID tag that requires a battery power supply. RFID system also exist wherein the RFID tag can be used either/or in passive/active mode, such RFID tags have great utility in especially in sealed devices where no physical access to the tag is possible after sealing.
Another vital need today is monitoring of devices especially in hospitals. Monitoring a device or equipment means reading a plurality of device parameters such as sensory data that requires a two-way communication between a wireless interrogator or transceiver and the device. Such a two-way communication usually requires a large amount of power, thereby draining the device battery. Low-power/Low data rate communication protocols such as Short Range Data (SRD)/IEEE 802.15.4/Bluetooth low energy (BLE) and the like are generally recommended for a two-way communication. Utilizing a global communication standard leads to communication interoperability between equipments procured from different vendors.
Further, any device driven by rechargeable batteries requires charging at regular intervals of time. RFID technology enables contactless charging of rechargeable batteries. Such contactless charging is becoming useful for medical devices especially where surgical equipments have battery sealed in an enclosure to maintain/enhance sterilization of such equipments. Contactless charging carries a far lower risk of electric shock when compared with conductive charging, as there are no exposed conductors. In case of contactless charging, the power source necessary for generating the power required to charge batteries is derived from the principles of energy harvesting. One of the methods is by deriving a DC voltage-current directly from a radio field (RF/Wireless). A typical set up consists of a radio-frequency transmitter which radiates at a given high frequency and power level as applicable. The RF field may or may not be modulated. The radiated RF field is captured by a receiver antenna and forwarded to a charging circuit; such circuit converts the RF field directly to DC at a given voltage level e.g. 3.3V. Such DC power is used to recharge batteries using trickle charging method. Majority of reliable implementations till this point of time, use near-field methods like magnetic coupling, electrostatic coupling etc which are limited to short ranges only. Longer range wireless charging method is becoming promising at UHF/microwave range (high gain antennas) and increased sensitivity of the receiver module. Ability to charge batteries using wireless over longer ranges is very useful when the battery driven device is completely sealed and batteries cannot be replaced further and where application needs permit longer hours of battery charging e.g. over night hours.
Therefore the three major potential needs for sealed equipment such as a sealed medical device are sealed enclosure with integrated battery charger & battery pack requiring contactless transfer of charge, asset tracking of such equipments especially in hospital environment, remote monitoring as well as actuation of such equipments using a management server such as hospital management server. More value addition may be brought in if the sealed equipments contain appropriate sized memory block to store critical manufacture/service data related to the particular equipment and Sensory data which will be retained for a long time.
However, only a system integration approach using standard products for incorporating all the above stated features cannot help as the space inside an equipment is a severe constraint. Further, battery power usage and very high degree of reliability is mandatory. Therefore, there is a need to devise a method that uses minimum hardware footprint, space constraint, high power efficiency, battery usage primarily reserved for the device operation, minimum interference effects, low cost and interoperability etc.
In order to solve the above mentioned problems, the present application proposes a system and method that utilizes a combination of distinct methods operating at a single frequency specifically using radio wave propagation as the fundamental physical phenomenon in a unique way to serve the need with minimalistic hardware.
Other features and advantages of the present invention will be explained in the following description of the invention having reference to the appended drawings.